A fluidic device, for example, a pneumatic valve array, is subject to wear during use, which will adversely impact its operational dependability to an increasing extent over time, and ultimately lead to malfunction or even to complete failure of the fluidic device. If a malfunction or failure has occurred, the fluidic device will then have to be repaired or replaced by an intact fluidic device. However, it is often better from a cost point of view to prevent the malfunction or complete failure by providing advance maintenance of the fluidic device in a timely manner.
However, it is difficult to ascertain an optimum maintenance timepoint, since this moment in time can depend on many factors, in particular on the particular strain on the fluidic device caused by its operation.
It is therefore the purpose of the present invention to design a diagnostic device for a fluidic device and also a fluidic device itself which will signal the necessary maintenance in a timely manner before occurrence of a malfunction or a total failure of the fluidic device.
This problem is solved by a diagnostic device for a fluidic device, in particular for a valve array, a fluidic actuator or a maintenance unit, which features a diagnostic means to ascertain at least one wear parameter causing wear on the fluidic device, and to report at least one wear status determined on the basis of the at least one wear parameter.
The problem is furthermore solved by a fluidic device equipped with this kind of diagnostic device.
The diagnostic device constantly determines the current wear status of the fluidic device, e.g., of a maintenance unit or a pneumatic or hydraulic valve array, based on the wear parameter. In this regard, the number of piston strokes of a valve can be determined, for example, and after a limit value is reached, the wear status may be signaled so that a valve head, gaskets on the valve, or similar items can be examined and replaced as needed. The diagnostic device monitors the functional integrity of the fluidic device and reports the wear status preferably in a preventive manner, i.e., before there is a malfunction or even total failure of the fluidic device.
Additional advantages of the invention are indicated from the dependent claims and from the description.
As has already been indicated above, the diagnostic features report the wear status, preferably in a preventive manner. The fluidic device is then at least partly operational and/or has limited operating capability, so that at least a kind of emergency operation will still be possible. However, it is preferable that the fluidic device still be fully operational even after the occurrence of the worn state.
Preferably, the fluidic device can still continue to be operated for a predefined time before the maintenance necessary to alleviate the wear status has to be performed.
It is preferably to locate the [diagnostic device] at or on the fluidic device.
For the wear parameters, according to this invention various quantities can be evaluated by the diagnostic device, of which only a few will be mentioned as examples. Preferably the diagnostic device will evaluate at least one load state of the fluidic device as a wear parameter. For example, it can count the working cycles of the fluidic device, determine the particular fluid consumption of the fluidic device, and/or it can evaluate the particular speed of motion of an actuator element, for example, a piston, of the fluidic device. It is also obvious that any particular combinations of wear parameters can be used, whereby the particular wear parameters can be differently weighted by the diagnostic device.
It is preferable that the diagnostic device be equipped to control and/or monitor the fluidic device. Also, the converse is possible, that the diagnostic device be a constituent of a control unit provided to control and/or monitor the fluidic device, in particular one that can be locally attached to or located at the fluidic device. In any case, in both the aforementioned configurations, the control, monitoring and diagnosis should be combined into a single unit.
Preferably the diagnostic features are designed to ascertain and/or report at least one interference parameter that signals a fault in the fluidic device. The diagnostic device then reports a fault in the fluidic device, for example, when its actuator element is no longer capable of movement and/or when overheating has occurred.
Preferably the diagnostic device contains output features for optical and/or acoustical output of the at least one wear status. The output features can also be located at a distance from the diagnostic device, but still be associated with it. The diagnostic device communicates with the output features by means of a line connection, for example, or by wireless means, e.g., by radio.
Preferably the diagnostic features are designed to indicate a need for at least one replacement part suitable for maintaining the functional integrity of the fluidic device. The diagnostic device then orders, more or less, the required spare part. For example, the diagnostic device can indicate in the message pertaining to the wear status, the spare parts' numbers of one or more required replacement parts which are needed to correct the wear status. A message of this kind is sent by the diagnostic device, preferably to a spare parts procurement apparatus, for example, a spare parts depot or such.
The message regarding the wear status of the fluidic device can be sent by the diagnostic device to various locations. Preferably it sends the message to a display unit located away from the fluidic device, for example, to an alerting device for maintenance personnel. The display device can be, for example, a pager, a mobile telephone or similar device. But the diagnostic device can also send the message to a higher-order control unit for control of the fluidic device, for example, to a central computer or similar unit, and/or to a neighboring fluidic device cooperating with the fluidic device being monitored by it. It is also similarly for a fault message which the diagnostic device can send to one of the aforementioned destinations.
Preferably the diagnostic device is equipped to execute an emergency program so that additional wear during continued operation of the fluidic device can be kept to a minimum or avoided entirely. For example, the operating speed of a pneumatic working cylinder can be reduced by means of the diagnostic device.
Of course, with regard to the diagnostic device, in principle the particular values for the at least one wear status and/or the at least one wear parameter can be predetermined as defaults, for example, as permanently programmed values. However, it is preferable that these values be parameterized, i.e., that they be variable for example by a user input and/or by an instruction transmitted by a higher-order controller.
Preferably the diagnostic device forms a constituent of the fluidic device. It can be permanently connected to the fluidic device, that is, it can be integrated into its housing or preferably also it can be designed as a replaceable module, for instance, as a circuitboard module that plugs into the fluidic device. Preferably the diagnostic device is designed as an integrated monochip microprocessor array whose component constituents form a single electronic assembly.
Preferably the diagnostic device contains program code that can be executed by a processor unit. Of course, it is self-evident that the diagnostic device can be designed entirely as a hardware component or entirely as a software component, or can have both hardware and software constituents.
A software diagnostic device according to this invention can be stored preferably on a storage medium, for example, on a diskette, a hard disk drive, a compact disc or similar device.
One design example of the invention will be explained in greater detail below.
We have: